What are the types of plant respiration?
Written by
Paul Reynolds
Reviewed by
Prof. Martin Thorne, Ph.D.Based on the availability of oxygen, plants mainly use two types of respiration. Aerobic respiration is an oxygen metabolism involving the release of the maximum energy. Anaerobic respiration is a form that operates without oxygen as an emergency resort. Most plants can operate in both modes of respiration and utilize the one that is best suited to their environment. This flexibility has enabled them to adapt to various environments and soil conditions, from marshy lands to deserts.
Aerobic Respiration
- Occurs in mitochondria with oxygen present
- Full glucose breakdown via glycolysis, Krebs cycle, and electron transport
- High energy yield: 36 ATP molecules per glucose molecule
- Byproducts: carbon dioxide and water vapor
- Dominant in well-oxygenated environments
Anaerobic Respiration
- Activates when oxygen drops below 5% concentration
- Partial glucose breakdown through fermentation pathways
- Low energy yield: only 2 ATP molecules per glucose
- Byproducts: ethanol and carbon dioxide
- Common in waterlogged roots or compacted soils
Mixed Mode Operation
- Plants combine both types based on tissue oxygen levels
- Roots often use anaerobic while leaves stay aerobic
- Transition takes minutes when oxygen availability changes
- Specialized plants like rice evolved for partial fermentation
- Energy trade-offs balance survival and growth needs
In ideal conditions, aerobic respiration prevails. The plant takes in soil oxygen through its roots, and atmospheric oxygen is absorbed through the stomata, allowing it to produce energy in large and effective quantities for growth and reproduction. The gardener maintains aerobic respiration as the principle of respiration by providing the right conditions, including porous and well-drained soil, and spacing the plants adequately to allow atmospheric oxygen to be available.
Anaerobic respiration induces stress symptoms, such as the yellowing of leaves and stunted growth. The end product of anaerobic respiration, ethanol, will, over time, result in damage to the root cells. However, plants provide recovery by producing aerenchyma air spaces. This adaptation is evident in the rice fields, where aerenchyma, or oxygen-transporting tissues, has developed. Such an adaptation is necessary so that plants in flooded situations can obtain oxygen more easily.
The type of respiration has implications for crop management practices. For example, rice paddies are intermittently aerated by growers to limit damage (ergo, high ethanol levels) caused by ethanol in the water. Greenhouse producers measure soil oxygen levels with specialized meters. Understanding these processes is relevant for selecting plants that can thrive in challenging conditions, such as rain gardens or compacted urban soils.
Read the full article: Respiration in Plants: The Complete Process Guide
